[PATCH AUTOSEL 6.1 19/26] null_blk: Fix: memory release when memory_backed=1

Sasha Levin
2023-06-16T10:31:13Z

From: Nitesh Shetty <nj.shetty@samsung.com>

[ Upstream commit 8cfb98196cceec35416041c6b91212d2b99392e4 ]

Memory/pages are not freed, when unloading nullblk driver.

Steps to reproduce issue
1.free -h
total used free shared buff/cache available
Mem: 7.8Gi 260Mi 7.1Gi 3.0Mi 395Mi 7.3Gi
Swap: 0B 0B 0B
2.modprobe null_blk memory_backed=1
3.dd if=/dev/urandom of=/dev/nullb0 oflag=direct bs=1M count=1000
4.modprobe -r null_blk
5.free -h
total used free shared buff/cache available
Mem: 7.8Gi 1.2Gi 6.1Gi 3.0Mi 398Mi 6.3Gi
Swap: 0B 0B 0B

Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Nitesh Shetty <nj.shetty@samsung.com>
Link: https://lore.kernel.org/r/20230605062354.24785-1-nj.shetty@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/block/null_blk/main.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index c45d09a9a9421..e8cb914223cdf 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -2194,6 +2194,7 @@ static void null_destroy_dev(struct nullb *nullb)
struct nullb_device *dev = nullb->dev;

null_del_dev(nullb);
+ null_free_device_storage(dev, false);
null_free_dev(dev);
}

--
2.39.2